CN118890050A - Strong current circuit filtering sampling circuit and device - Google Patents
Strong current circuit filtering sampling circuit and device Download PDFInfo
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Abstract
The invention discloses a strong current circuit filtering sampling circuit and a device, wherein the circuit comprises: the device comprises a sampling module, a primary filtering module, a signal conditioning module and a secondary filtering module; the sampling module obtains a sampling signal from the sampled circuit; the first-stage filtering module performs passive filtering on the sampling signal; the signal conditioning and secondary filtering module performs active filtering on the sampling signal subjected to passive filtering. The invention can sample the strong current side voltage or current, and simultaneously isolate, filter and convert the strong current side voltage or current, and feed back signals to the control loop, thereby solving the problem of easy interference in the prior art.
Description
Technical Field
The invention relates to the field of strong current circuits, in particular to a strong current circuit filtering sampling circuit and a device.
Background
Voltage or current in the power loop is typically detected in power electronics for implementing control algorithms or protection functions of the circuit. The detected circuit is generally a strong current side, hundreds of volts to kilovolts can be generated according to different products, and the power electronic device can generate relatively large interference when being switched on and off at a high speed, and the sampling signal is fed back to the control system and is generally a safe low-voltage side, so that the sampling circuit is required to have the functions of sampling an analog signal, converting the analog signal into a level which can be received by a control loop, filtering the signal, and guaranteeing safe isolation, and the existing sampling circuit cannot meet the requirements at the same time.
Disclosure of Invention
The embodiment of the invention provides a strong current circuit filtering sampling circuit and a strong current circuit filtering sampling device, which are used for filtering and sampling technology after detecting voltage or current in a high-power loop and effectively feeding back an isolated signal to a control loop.
To achieve the above object, a first aspect of an embodiment of the present application provides a strong current circuit filtering sampling circuit, including: the device comprises a sampling module, a primary filtering module, a signal conditioning module and a secondary filtering module;
The first input end of the sampling module is connected with a first sampling end of an external sampled circuit, the second input end of the sampling module is connected with a second sampling end of the external sampled circuit, the first output end of the sampling module is connected with the first input end of the primary filtering module, and the second output end of the sampling module is connected with the second input end of the primary filtering module; the first output end of the primary filtering module is connected with the first input end of the signal conditioning and secondary filtering module, and the second output end of the primary filtering module is connected with the second input end of the signal conditioning and secondary filtering module; the output end of the signal conditioning and secondary filtering module is connected with an external control system circuit;
The sampling module obtains a sampling signal from the sampled circuit;
The first-stage filtering module performs passive filtering on the sampling signal;
The signal conditioning and secondary filtering module performs active filtering on the sampling signal subjected to passive filtering.
In a possible implementation manner of the first aspect, when the sampling signal is a voltage signal, the sampling module includes a first resistor string and a second resistor string; the first resistor string and the second resistor string have the same structure; the input end of the first resistor string is connected with a first sampling end of an external sampled circuit, and the input end of the first resistor string is connected with a first input end of the primary filtering module; the first sampling end of the second resistor string and the external sampled circuit are connected with the second sampling end of the external sampled circuit, and the input end of the second resistor string is connected with the second input end of the first-stage filtering module.
In a possible implementation manner of the first aspect, when the sampling signal is a current signal, the sampling module includes a first resistor string, a second resistor string, and a first resistor; the first resistor string and the second resistor string have the same structure; the input end of the first resistor string is respectively connected with a first sampling end of an external sampled circuit and one end of the first resistor, and the input end of the first resistor string is respectively connected with the first input end of the first-stage filtering module and the other end of the first resistor; the first sampling end of the second resistor string and the external sampled circuit are connected with the second sampling end of the external sampled circuit, and the input end of the second resistor string is connected with the second input end of the first-stage filtering module.
In a possible implementation manner of the first aspect, the first resistor string and the second resistor string each include a plurality of sub resistors connected in series; and the resistance values of the sub-resistors corresponding to the structures in the first resistor string and the second resistor string are equal.
In a possible implementation manner of the first aspect, the first stage filtering module includes a differential mode filtering capacitor, a first common mode filtering capacitor and a second common mode filtering capacitor;
One end of the differential mode filter capacitor is connected with the first output end of the sampling module, and the other end of the differential mode filter capacitor is connected with one end of the first common mode filter capacitor and the second output end of the sampling module;
one end of the first common mode filter capacitor is connected with the second input end of the signal conditioning and secondary filter module, and the other end of the first common mode filter capacitor and one end of the second common mode filter capacitor are grounded;
The other end of the second common mode filter capacitor is connected with the first input end of the signal conditioning and secondary filtering module.
In a possible implementation manner of the first aspect, capacitance values of the first common mode filter capacitor and the second common mode filter capacitor are equal.
In a possible implementation manner of the first aspect, when the sampling signal is a dc signal, the signal conditioning and secondary filtering module includes a second resistor, a third resistor, a first reference resistor, a second reference resistor, a first capacitor, a second capacitor, and an operational amplifier;
one end of the second resistor is respectively connected with the first output end of the first stage filtering module and one end of the first reference resistor, and the other end of the second resistor is connected with the first input end of the operational amplifier and one end of the first capacitor;
the output end of the operational amplifier is respectively connected with the other end of the first capacitor, the other end of the first reference resistor and an external control system circuit;
one end of the third resistor is respectively connected with the second output end of the first-stage filtering module and one end of the second reference resistor, and the other end of the third resistor is respectively connected with the second input end of the operational amplifier and one end of the second capacitor;
The other end of the second reference resistor and the other end of the second capacitor are grounded.
In a possible implementation manner of the first aspect, when the sampling signal is an ac signal, the signal conditioning and secondary filtering module includes a second resistor, a third resistor, a first reference resistor, a second reference resistor, a first capacitor, a second capacitor, an operational amplifier, and a bias voltage source;
one end of the second resistor is respectively connected with the first output end of the first stage filtering module and one end of the first reference resistor, and the other end of the second resistor is connected with the first input end of the operational amplifier and one end of the first capacitor;
the output end of the operational amplifier is respectively connected with the other end of the first capacitor, the other end of the first reference resistor and an external control system circuit;
one end of the third resistor is respectively connected with the second output end of the first-stage filtering module and one end of the second reference resistor, and the other end of the third resistor is respectively connected with the second input end of the operational amplifier and one end of the second capacitor;
The output end of the bias voltage source is connected with the other end of the second reference resistor;
The other end of the second capacitor is grounded.
In a possible implementation manner of the first aspect, a difference between a cut-off frequency and an interference frequency of the signal conditioning and secondary filtering module is smaller than a preset threshold.
A second aspect of an embodiment of the present application provides a strong electric circuit filtering sampling device, including a strong electric circuit filtering sampling circuit as described above.
Compared with the prior art, the strong current circuit filtering sampling circuit and the device provided by the embodiment of the invention have the advantages that the whole circuit is composed of a sampling module, a primary filtering module and a signal conditioning and secondary filtering module. The sampling module is responsible for obtaining signals from the sampled circuit, the primary filtering module performs primary passive filtering, the signal conditioning and secondary filtering module further performs active filtering and signal conditioning, and finally the processed signals are sent to the control system circuit. For the voltage signal, the sampling module comprises two resistor strings with the same structure, and the resistor strings are respectively connected with two ends of a sampled circuit to ensure accurate sampling of the signal; for a current signal, besides a resistor string, the sampling module also introduces an additional resistor to realize the conversion from current to voltage, so that the subsequent processing is convenient. The first-stage filtering module adopts a differential mode filtering capacitor for filtering differential mode noise among signals and a common mode filtering capacitor for suppressing common mode interference and enhancing signal purity. The signal conditioning and secondary filtering module can be switched into different active filtering circuits according to the signal type (direct current or alternating current), so that the signal quality is further improved.
The filter sampling circuit design of the embodiment of the invention gives consideration to the processing requirements of different signal types, obviously improves the signal quality through multi-level filtering and conditioning, and is suitable for precision measurement and control application in a strong current environment.
Drawings
FIG. 1 is a schematic diagram showing a connection of a filtering and sampling circuit of a strong current circuit according to an embodiment of the present invention;
FIG. 2 is a schematic circuit diagram of a sampling module according to an embodiment of the present invention;
FIG. 3 is a schematic circuit diagram of another sampling module according to an embodiment of the present invention;
FIG. 4 is a schematic circuit diagram of a first stage filter module according to an embodiment of the present invention;
FIG. 5 is a schematic circuit diagram of a signal conditioning and two-stage filtering module according to an embodiment of the present invention;
fig. 6 is a schematic circuit diagram of another signal conditioning and two-stage filtering module according to an embodiment of the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In order to solve the above-mentioned problems, referring to fig. 1, an embodiment of the present invention provides a filtering sampling circuit of a strong current circuit, which includes: the device comprises a sampling module 1, a primary filtering module 2, a signal conditioning and secondary filtering module 3.
The first input end of the sampling module 1 is connected with a first sampling end of an external sampled circuit, the second input end of the sampling module 1 is connected with a second sampling end of the external sampled circuit, the first output end of the sampling module 1 is connected with the first input end of the primary filtering module 2, and the second output end of the sampling module 1 is connected with the second input end of the primary filtering module 2; the first output end of the primary filtering module 2 is connected with the first input end of the signal conditioning and secondary filtering module 3, and the second output end of the primary filtering module 2 is connected with the second input end of the signal conditioning and secondary filtering module 3; the output end of the signal conditioning and secondary filtering module 3 is connected with an external control system circuit.
The sampling module 1 obtains a sampling signal from the sampled circuit.
The primary filtering module 2 performs passive filtering on the sampled signal.
The signal conditioning and secondary filtering module 3 performs active filtering on the passively filtered sampling signal.
The embodiment is particularly suitable for an application scene of collecting signals from a high-power or high-pressure environment and purifying and conditioning the signals, and the following is deep analysis of the action of each module:
In the whole working flow, the sampling module 1 is used as an inlet for signal acquisition, and extracts signals from an external sampled circuit. Under high-current conditions, sampling modules are often required to have high voltage endurance and good electrical isolation to ensure safe signal capture. The primary filtering module 2 is mainly responsible for passive filtering, and a filtering network can be constructed by using passive elements (such as a capacitor and an inductor) to remove high-frequency noise and interference components in signals. The advantage of a passive filter is that it is simple and reliable, does not require an external power supply, but may not be as active as the filter in terms of accuracy and dynamic adjustment of the filter characteristics. The signal conditioning and secondary filtering module 3 serves as a core processing unit of the circuit, and the signal conditioning and secondary filtering module bears the tasks of signal optimization and depth filtering. Signal conditioning may include amplification, impedance matching, unbiasing, etc., to ensure that the level and characteristics of the signal are suitable for subsequent processing. The second-stage filtering uses active devices (such as operational amplifiers) to realize more complex filtering functions, such as bandpass, bandstop, lowpass or highpass filtering, so as to further improve the purity of the signal.
Finally, the conditioned and filtered signals are transmitted to an external control system circuit through the output end of the signal conditioning and secondary filtering module for subsequent data analysis, display or control decision. The circuit design of the embodiment ensures that high-quality and low-noise signals can be obtained even in a severe strong-current environment, and provides a basis for stable operation and accurate control of the system. In a specific design, electromagnetic compatibility (EMC), thermal design, cost, and size are also considered to achieve an optimal balance of performance and practicality.
Compared with the prior art, the strong current circuit filtering sampling circuit provided by the embodiment of the invention is characterized in that the whole circuit consists of a sampling module, a primary filtering module and a signal conditioning and secondary filtering module. The sampling module is responsible for obtaining signals from the sampled circuit, the primary filtering module performs primary passive filtering, the signal conditioning and secondary filtering module further performs active filtering and signal conditioning, and finally the processed signals are sent to the control system circuit. For the voltage signal, the sampling module comprises two resistor strings with the same structure, and the resistor strings are respectively connected with two ends of a sampled circuit to ensure accurate sampling of the signal; for a current signal, besides a resistor string, the sampling module also introduces an additional resistor to realize the conversion from current to voltage, so that the subsequent processing is convenient. The first-stage filtering module adopts a differential mode filtering capacitor for filtering differential mode noise among signals and a common mode filtering capacitor for suppressing common mode interference and enhancing signal purity. The signal conditioning and secondary filtering module can be switched into different active filtering circuits according to the signal type (direct current or alternating current), so that the signal quality is further improved.
Illustratively, when the sampling signal is a voltage signal, the sampling module 1 includes a first resistor string and a second resistor string; the first resistor string and the second resistor string have the same structure; the input end of the first resistor string is connected with a first sampling end of an external sampled circuit, and the input end of the first resistor string is connected with a first input end of the primary filtering module; the first sampling end of the second resistor string and the external sampled circuit are connected with the second sampling end of the external sampled circuit, and the input end of the second resistor string is connected with the second input end of the first-stage filtering module.
The sampling module is set according to the type of the signal to be sampled by the system, if the sampled signal is voltage, the circuit structure is as shown in fig. 2, and the inputs are respectively connected with two ends of the circuit which needs to sample the voltage. The setting of R is generally tens to hundreds of kΩ according to the magnitude of the sampling voltage and the requirements of the system safety rule, wherein R 11＝R21,R12＝R22,……R1n＝R2n. When the system requires a higher isolation voltage and a larger safety distance, more resistors and larger values of resistance may be employed.
Illustratively, when the sampling signal is a current signal, the sampling module includes a first resistor string, a second resistor string, and a first resistor Rs; the first resistor string and the second resistor string have the same structure; the input end of the first resistor string is respectively connected with a first sampling end of an external sampled circuit and one end of the first resistor, and the input end of the first resistor string is respectively connected with the first input end of the first-stage filtering module and the other end of the first resistor; the first sampling end of the second resistor string and the external sampled circuit are connected with the second sampling end of the external sampled circuit, and the input end of the second resistor string is connected with the second input end of the first-stage filtering module.
If the sampled signal is current, as shown in FIG. 3, R s is connected in series in the circuit to be sampled, and then the voltage across the resistor is detected. R s takes on the current magnitude which is sampled according to the requirement, and is usually a few mΩ to a few tens of mΩ.
Therefore, the total equivalent resistance of the sampling module is:
Rc＝R11+R12+R13……+R1n；
illustratively, the first resistor string and the second resistor string each include a plurality of series-connected sub-resistors; and the resistance values of the sub-resistors corresponding to the structures in the first resistor string and the second resistor string are equal.
Illustratively, the first stage filter module 2 includes a differential mode filter capacitor C L11, a first common mode filter capacitor C L12, and a second common mode filter capacitor C L13.
One end of the differential mode filter capacitor C L11 is connected with the first output end of the sampling module 1, and the other end of the differential mode filter capacitor C L11 is connected with one end of the first common mode filter capacitor C L12 and the second output end of the sampling module 1;
One end of the first common-mode filter capacitor C L12 is connected to the second input end of the signal conditioning and secondary filter module 3, and the other end of the first common-mode filter capacitor C L12 and one end of the second common-mode filter capacitor C L13 are both grounded;
The other end of the second common-mode filter capacitor C L13 is connected with the first input end of the signal conditioning and secondary filtering module 3.
The primary filter module circuit performs passive filtering on the sampled signals, and the circuit schematic diagram is shown in fig. 4, and the primary filter module circuit is respectively composed of a differential mode filter capacitor C L11 and a common mode filter capacitor C L12,CL13. The setting of the capacitor is selected according to the length of the sampling wiring, the interference intensity of the system and the delay requirement of the sampling signal. For the common design, C L11,CL12,CL13 is generally taken as 1nF, if the sampling noise interference is too large, the capacitance value is increased to carry out test confirmation, and if the sampling noise interference is changed to 10nF. Under the condition of meeting noise filtering, the value of the filter capacitor is reduced as much as possible so as to reduce the influence on the sampling signal. Typically several hundred pF to several tens nF, and C L12＝CL13.
Illustratively, the first common-mode filter capacitor C L12 and the second common-mode filter capacitor C L13 have equal capacitance values.
Illustratively, when the sampling signal is a dc signal, the signal conditioning and secondary filtering module 3 includes a second resistor R L21, a third resistor R L22, a first reference resistor R F1, a second reference resistor R F2, a first capacitor C L21, a second capacitor C L22, and an operational amplifier U.
One end of the second resistor R L21 is respectively connected to the first output end of the first stage filtering module 2 and one end of the first reference resistor R F1, and the other end of the second resistor R L21 is connected to the first input end of the operational amplifier U and one end of the first capacitor C L21.
The output end of the operational amplifier U is respectively connected with the other end of the first capacitor C L21, the other end of the first reference resistor R F1 and an external control system circuit.
One end of the third resistor R L22 is connected to the second output end of the first stage filtering module 2 and one end of the second reference resistor R F2, and the other end of the third resistor R L22 is connected to the second input end of the operational amplifier U and one end of the second capacitor C L22.
The other end of the second reference resistor R F2 and the other end of the second capacitor C L22 are grounded.
The signal conditioning and secondary filtering circuit is connected after the primary filtering circuit, the module realizes the level conditioning of the sampling signal, and is matched with the resistance value of the sampling module, so that the signal can be amplified or reduced, the bias of the signal can be realized through connecting the reference voltage, for example, the bias voltage of 1.65V can be connected to a 3.3V signal system, the bias voltage of 2.5V can be connected to a 5V signal system, and meanwhile, the active filtering of the signal is realized through the setting of the filtering resistor and the capacitor, so that the quality of the output signal is improved. As shown in fig. 5, U is an operational amplifier, and the equivalent resistance of the sampling module is R C, then the gain coefficient of the signal is:
The signal is amplified or reduced by different resistor settings. The signal can be subjected to reverse phase conditioning by accessing different positive and negative poles of the operational amplifier. If the sampling circuit of fig. 2 is used, and R11＝R12＝R13＝R14＝R15＝100kΩ,R21＝R22＝R23＝R24＝R25＝100kΩ, is used, then R C =500 kΩ, referring to fig. 5 or 6, if R f =10kΩ is taken, then the signal gain is 1/50, i.e. when the sampling input voltage is 50V, the sampling output voltage is 1V, i.e.:
Vout＝G×Vin
The setting of R L and C L and the first-stage filtering module of the previous stage form a second-order active filtering circuit together, the value R L21＝RL22,CL21＝CL22 is usually taken, the value of the resistance and the value of the capacitance are selected according to the interference intensity and the delay requirement of the system, the filtering cut-off frequency of the active filtering circuit is calculated as follows, and the cut-off frequency of the filtering circuit is set in the preset range of the frequency of main interference, so that the optimal filtering effect can be obtained. It is also possible to determine whether the set filter cut-off frequency has a good filtering effect by testing. The cut-off frequency is typically set at a sampling signal frequency greater than 10 times:
wherein, R f＝Rf1＝Rf2.
Illustratively, when the sampled signal is an ac signal, the signal conditioning and secondary filtering module 3 includes a second resistor R L21, a third resistor R L22, a first reference resistor R F1, a second reference resistor R F2, a first capacitor C L21, a second capacitor C L22, an operational amplifier, and a bias voltage source V REF.
One end of the second resistor R L21 is respectively connected to the first output end of the first stage filtering module 2 and one end of the first reference resistor R F1, and the other end of the second resistor R L21 is connected to the first input end of the operational amplifier U and one end of the first capacitor C L21.
The output end of the operational amplifier U is respectively connected with the other end of the first capacitor C L21, the other end of the first reference resistor R F1 and an external control system circuit;
One end of the third resistor R L22 is connected to the second output end of the first stage filtering module 2 and one end of the second reference resistor R F2, and the other end of the third resistor R L22 is connected to the second input end of the operational amplifier U and one end of the second capacitor C L22.
The output end of the bias voltage source V REF is connected with the other end of the second reference resistor R F2.
The other end of the second capacitor C L22 is grounded.
If the sampling signal is an ac signal and the signal needs to be biased, the sampling is in the circuit form as shown in fig. 6, and the output voltage is biased by accessing the reference voltage V ref. If the voltage is to 3.3V signal system, 1.65V bias voltage can be connected, and if the voltage is to 5V signal system, 2.5V bias voltage can be connected, the reference voltage is set according to the offset required by the signal, so that the output voltage range meets the input requirement of the control system, namely.
Vout＝Vref+G×Vin
The difference between the cut-off frequency and the interference frequency of the signal conditioning and secondary filtering module 3 is illustratively smaller than a preset threshold value.
Compared with the prior art, the strong current circuit filtering sampling circuit provided by the embodiment of the invention is characterized in that the whole circuit consists of a sampling module, a primary filtering module and a signal conditioning and secondary filtering module. The sampling module is responsible for obtaining signals from the sampled circuit, the primary filtering module performs primary passive filtering, the signal conditioning and secondary filtering module further performs active filtering and signal conditioning, and finally the processed signals are sent to the control system circuit. For the voltage signal, the sampling module comprises two resistor strings with the same structure, and the resistor strings are respectively connected with two ends of a sampled circuit to ensure accurate sampling of the signal; for a current signal, besides a resistor string, the sampling module also introduces an additional resistor to realize the conversion from current to voltage, so that the subsequent processing is convenient. The first-stage filtering module adopts a differential mode filtering capacitor for filtering differential mode noise among signals and a common mode filtering capacitor for suppressing common mode interference and enhancing signal purity. The signal conditioning and secondary filtering module can be switched into different active filtering circuits according to the signal type (direct current or alternating current), so that the signal quality is further improved.
In summary, the filter sampling circuit provided in the above embodiment has a fine design, meets the processing requirements of different signal types, remarkably improves the signal quality through multi-level filtering and conditioning, and is suitable for precision measurement and control application in a strong current environment.
An embodiment of the application provides a strong electric circuit filtering sampling device, which comprises the strong electric circuit filtering sampling circuit.
It will be clear to those skilled in the art that for convenience and brevity of description, reference may be made to the corresponding processes in the foregoing circuit embodiments for the specific operation of the apparatus described above, which will not be further described herein.
Compared with the prior art, the strong circuit filtering sampling device provided by the embodiment of the invention has the advantages that the whole circuit is composed of a sampling module, a primary filtering module and a signal conditioning and secondary filtering module. The sampling module is responsible for obtaining signals from the sampled circuit, the primary filtering module performs primary passive filtering, the signal conditioning and secondary filtering module further performs active filtering and signal conditioning, and finally the processed signals are sent to the control system circuit. For the voltage signal, the sampling module comprises two resistor strings with the same structure, and the resistor strings are respectively connected with two ends of a sampled circuit to ensure accurate sampling of the signal; for a current signal, besides a resistor string, the sampling module also introduces an additional resistor to realize the conversion from current to voltage, so that the subsequent processing is convenient. The first-stage filtering module adopts a differential mode filtering capacitor for filtering differential mode noise among signals and a common mode filtering capacitor for suppressing common mode interference and enhancing signal purity. The signal conditioning and secondary filtering module can be switched into different active filtering circuits according to the signal type (direct current or alternating current), so that the signal quality is further improved.
The filter sampling circuit design of the embodiment of the invention gives consideration to the processing requirements of different signal types, obviously improves the signal quality through multi-level filtering and conditioning, and is suitable for precision measurement and control application in a strong current environment.
In order to achieve the above purpose, the embodiment of the invention further provides a sampling device. The sampling device comprises a sampling circuit as described above. The test equipment can adopt the technical schemes of all the embodiments, so that the test equipment has at least the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.
Claims (10)
1. A strong electric circuit filtering sampling circuit, comprising: the device comprises a sampling module, a primary filtering module, a signal conditioning module and a secondary filtering module;
The first input end of the sampling module is connected with a first sampling end of an external sampled circuit, the second input end of the sampling module is connected with a second sampling end of the external sampled circuit, the first output end of the sampling module is connected with the first input end of the primary filtering module, and the second output end of the sampling module is connected with the second input end of the primary filtering module; the first output end of the primary filtering module is connected with the first input end of the signal conditioning and secondary filtering module, and the second output end of the primary filtering module is connected with the second input end of the signal conditioning and secondary filtering module; the output end of the signal conditioning and secondary filtering module is connected with an external control system circuit;
The sampling module obtains a sampling signal from the sampled circuit;
The first-stage filtering module performs passive filtering on the sampling signal;
The signal conditioning and secondary filtering module performs active filtering on the sampling signal subjected to passive filtering.
2. The filtering sampling circuit of claim 1, wherein when the sampling signal is a voltage signal, the sampling module comprises a first resistor string and a second resistor string; the first resistor string and the second resistor string have the same structure; the input end of the first resistor string is connected with a first sampling end of an external sampled circuit, and the input end of the first resistor string is connected with a first input end of the primary filtering module; the first sampling end of the second resistor string and the external sampled circuit are connected with the second sampling end of the external sampled circuit, and the input end of the second resistor string is connected with the second input end of the first-stage filtering module.
3. The filtering sampling circuit of claim 1, wherein when the sampling signal is a current signal, the sampling module comprises a first resistor string, a second resistor string, and a first resistor; the first resistor string and the second resistor string have the same structure; the input end of the first resistor string is respectively connected with a first sampling end of an external sampled circuit and one end of the first resistor, and the input end of the first resistor string is respectively connected with the first input end of the first-stage filtering module and the other end of the first resistor; the first sampling end of the second resistor string and the external sampled circuit are connected with the second sampling end of the external sampled circuit, and the input end of the second resistor string is connected with the second input end of the first-stage filtering module.
4. A strong current circuit filtering sampling circuit as defined in claim 2 or 3, wherein said first resistor string and said second resistor string each comprise a plurality of series-connected sub-resistors; and the resistance values of the sub-resistors corresponding to the structures in the first resistor string and the second resistor string are equal.
5. The filtering sampling circuit of claim 1, wherein the first stage filtering module comprises a differential mode filter capacitor, a first common mode filter capacitor and a second common mode filter capacitor;
One end of the differential mode filter capacitor is connected with the first output end of the sampling module, and the other end of the differential mode filter capacitor is connected with one end of the first common mode filter capacitor and the second output end of the sampling module;
one end of the first common mode filter capacitor is connected with the second input end of the signal conditioning and secondary filter module, and the other end of the first common mode filter capacitor and one end of the second common mode filter capacitor are grounded;
The other end of the second common mode filter capacitor is connected with the first input end of the signal conditioning and secondary filtering module.
6. The filtering sampling circuit of claim 5, wherein the first common-mode filter capacitor and the second common-mode filter capacitor have equal capacitance values.
7. The filtering and sampling circuit of claim 1, wherein when the sampling signal is a dc signal, the signal conditioning and secondary filtering module comprises a second resistor, a third resistor, a first reference resistor, a second reference resistor, a first capacitor, a second capacitor, and an operational amplifier;
one end of the second resistor is respectively connected with the first output end of the first stage filtering module and one end of the first reference resistor, and the other end of the second resistor is connected with the first input end of the operational amplifier and one end of the first capacitor;
the output end of the operational amplifier is respectively connected with the other end of the first capacitor, the other end of the first reference resistor and an external control system circuit;
one end of the third resistor is respectively connected with the second output end of the first-stage filtering module and one end of the second reference resistor, and the other end of the third resistor is respectively connected with the second input end of the operational amplifier and one end of the second capacitor;
The other end of the second reference resistor and the other end of the second capacitor are grounded.
8. The filtering and sampling circuit of claim 1, wherein when the sampling signal is an ac signal, the signal conditioning and secondary filtering module comprises a second resistor, a third resistor, a first reference resistor, a second reference resistor, a first capacitor, a second capacitor, an operational amplifier, and a bias voltage source;
one end of the second resistor is respectively connected with the first output end of the first stage filtering module and one end of the first reference resistor, and the other end of the second resistor is connected with the first input end of the operational amplifier and one end of the first capacitor;
the output end of the operational amplifier is respectively connected with the other end of the first capacitor, the other end of the first reference resistor and an external control system circuit;
one end of the third resistor is respectively connected with the second output end of the first-stage filtering module and one end of the second reference resistor, and the other end of the third resistor is respectively connected with the second input end of the operational amplifier and one end of the second capacitor;
The output end of the bias voltage source is connected with the other end of the second reference resistor;
The other end of the second capacitor is grounded.
9. The filtering and sampling circuit of claim 1, wherein the difference between the cut-off frequency and the interference frequency of the signal conditioning and secondary filtering module is less than a predetermined threshold.
10. A strong electric circuit filtering sampling device, characterized in that it comprises a strong electric circuit filtering sampling circuit according to any one of claims 1-8.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410900598.3A CN118890050A (en) | 2024-07-05 | 2024-07-05 | Strong current circuit filtering sampling circuit and device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410900598.3A CN118890050A (en) | 2024-07-05 | 2024-07-05 | Strong current circuit filtering sampling circuit and device |
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| Publication Number | Publication Date |
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| CN118890050A true CN118890050A (en) | 2024-11-01 |
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|---|---|---|---|
| CN202410900598.3A Pending CN118890050A (en) | 2024-07-05 | 2024-07-05 | Strong current circuit filtering sampling circuit and device |
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| Country | Link |
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| CN (1) | CN118890050A (en) |
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- 2024-07-05 CN CN202410900598.3A patent/CN118890050A/en active Pending
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